Which of these must drivers do when making a lane change?

When making a lane change, it is essential for drivers to check over their shoulders. This action allows them to have a clear view of any vehicles that may be in their blind spots, which are areas not visible in the mirrors. This step is crucial for ensuring safety because blind spots can hide the presence of cars, motorcycles, or bicycles nearby.

By checking over their shoulders, drivers can confirm that there is enough space to make a lane change and that it is safe to proceed. This part of the process complements the use of mirrors and signaling, helping to avoid accidents and maintain safe driving practices.